Curable compositions including reactively end-capped poly(arylene ether) resins and copolymerizable monomers have been described, for example, in U.S. Pat. No. 5,071,922 to Nelissen et al., and U.S. Pat. Nos. 6,352,782 and 6,627,704 to Yeager et al., as well as U.S. Statutory Invention Registration No. H521 to Fan. The compositions described therein are useful in a wide variety of thermoset applications, but existing formulations lack the balance of properties that is desired for fabricating plastic-packaged electronic devices. In particular, there is a need for improved flow during molding without sacrificing post-cure physical properties such as stiffness and impact strength.